The sheet music indicated is for the original song, which will be why it seems unfamiliar. All Revival performers, so far as I can tell, sing instead forms of the song derived from the Copper Family of Rottingdean in Sussex. How convincingly they do it depends, largely, on how much attention they have paid. Mary Black got it from her brother Shay, I think, who learned it from Nic Jones, who learned it from the Coppers. Nic regularised rather the more interesting rhythmic phrasing the Coppers had developed, and Mary reduced it still further, singing it more or less as a standard Country and Western piece. Pretty, but diluted; and I think that she did not credit either the composers of the song or the Coppers, who rather improved it.

All this has already been gone over in considerable detail in previous discussions here. Probably we should just stick to "the chords" now, for people who need accompaniment to carry it for them. It seems unlikely that anything much that is new is likely to come up.